1. Technical Field
This disclosure relates to an apparatus for generating extreme ultraviolet (EUV) light.
2. Related Art
With recent increase in integration of semiconductor process, transfer patterns for use in photolithography of the semiconductor process have rapidly become finer. In the next generation, microfabrication at 70 to 45 nm, and further, microfabrication at 32 nm or less is to be demanded. Accordingly, for example, to meet the demand for microfabrication at 32 nm or less, an exposure apparatus is expected to be developed, where EUV light of a wavelength of approximately 13 nm is combined with a reduction projection reflective optical system.
There are mainly three types of known EUV light generation apparatuses, namely, a laser produced plasma (LPP) type apparatus using plasma produced as a target material is irradiated with a laser beam, a discharge produced plasma (DPP) type apparatus using plasma produced by discharge, and a synchrotron radiation (SR) type apparatus using orbital radiation.